1. Field of the Invention
The present invention relates to an electric pen used as a portable personal information device.
2. Description of the Related Art
There have been known a variety of pointing devices for inputting desired positional and direction data to a computer. One typical example of a pointing device is a mouse unit. In one type of mouse unit, positional and direction data are inputted to the computer by moving the mouse unit itself over the top of a surface such as a desk top. Moving the mouse unit in this way rotates a ball mounted internally to the mouse unit. The direction and amount that the ball rotates is transmitted to a roller in abutting contact with the ball. In this way, the distance and direction in which the mouse unit moves is detected and inputted to the computer. There is also known an optical mouse unit which emits light to illuminate a mouse pad provided with a special lattice at its upper surface. The distance and direction of movement of the mouse unit can be determined by the pattern of reflected light and inputted to the computer.
Recently, input devices that are more user compatible than mouse units have been developed. One example is pen input systems which include a tablet and a special pen. The tablet can be a liquid crystal display or a special optical tablet and is provided with a transparent conductive film. The special pen is provided with a conductive tip. The position and speed of the pen tip can be detected by bringing the pen tip into contact with the transparent conductive film.
Various output devices have been used with these input devices. Normally, output devices of ink jet type, electrophotographic type, silver halide photographic type, or thermal transfer type are used for outputting a hard copy. However, all of these devices are desk top units and therefore are not portable.
Japanese Utility Model Application (KOKAI) No. HEI-4-94693 describes an electric pen including a compact ink jet type printing mechanism. Because the printing mechanism is formed in the shape of a pen, a user can electrically print in a desired color with the same feel as though writing with a pencil or ordinary pen. The electric pen is provided with an analog type color-adjustment switch which a user operates to select a desired color. The electric pen is also provided with an ejection switch which the user presses to cause the electric pen to eject droplets of colored ink. The droplets will impinge on a print medium at a position indicated by the user pointing the electric pen. However, the electric pen is an independent electric writing tool and is only usable to print when the user indicates what to print.
There has been a demand for a device which allows a user to input and output to and from an external data processor, such as a portable information device, with the same feel as through writing with a pen. However, such a device with sufficient functions has yet to be realized.